a complement that expresses a proposition which contains information that is unknown. Interrogative complements commonly occur in certain types of propositional attitude - complement clause constructions. Examples: in I wonder who is going to the party or John wondered whether he would go to the party, who is going to the party and whether he would go to the party are interrogative complements. Interrogative complements are often found in the objective construal of epistemic modality. (Sections 12.3.4, 18.3.1)